It has been found that when certain types of house lap siding, particularly including fiber cement lap siding (e.g., “Hardiplank”® lap siding available from James Hardie Building Products, Mission Viejo, Calif.; or “WeatherBoard”™ lap siding available from CertainTeed Corporation, Valley Forge, Pa.), is nailed directly to or over underlying structure such as polymeric house wrap (e.g., “Tyvec”® Home Wrap® available from DuPont) covered sheathing (e.g., sheets of pressboard or plywood) attached to the outside of wood house framing, water can get between the siding and the underlying structure and cause mold to grow therebetween. In some such instances, it has been necessary to remove and replace the siding and parts of the underlying structure to correct that problem.
It is recognized that to alleviate this problem a ventilation space (e.g., a ¼ inch ventilation space) should be provided between the rear surface of the siding and the underlying structure through which ventilation space air can circulate to dry moisture and restrict the growth of mold. Two known methods have been used to provide that ventilation space.                (1) Vertical baton strips (e.g., strips about 2 inches wide and ¼ inch thick) extending vertically from the bottom to the top of the underlying structure, spaced at about 16 inches and aligned with the studs behind the sheathing have been used between the siding and underlying structure to provide such a ventilation space. That ventilation space is only provided between the vertical strips so that horizontal cross ventilation is restricted. Also, nailing the lap siding to those strips can cause visible bows about horizontal axes in the lengths of siding between their upper portions that are nailed to the strips and their lower portions that extend over the upper portions of the lengths of siding below them.        (2) A stiff resiliently flexible corrugated sheet random woven of Nylon polymeric fibers to provide a high percentage of openings through the corrugated sheet (e.g., the “Home Slicker”® corrugated sheet sold by Benjamin Obdyke Incorporated, Horsham, Pa., see U.S. Pat. No. 6,594,965) is positioned between the lengths of siding and the underlying structure with its corrugations extending vertically to provide such a ventilation space. The ventilation space provided by that porous corrugated sheet is somewhat occluded by the presence of the corrugated sheet. Also, nailing the lengths of siding to the underlying structure through the corrugated sheet can collapse the corrugations in the sheet under the nailed portions of the siding, whereas the portions of the siding between the nailed portions are held away from the underlayment by the corrugated sheet, thereby causing visible bows in the siding about vertical axes between those nailed portions.        